The Sagamaok-Anishnawbek First Nation is currently under lockdown.
Its chief, Paul Eshkakogan says the lockdown is in response to a serious violent situation, but did not specify.
First Nations residents are being asked to lock their doors and remain inside; the OPP has now joined the Sudbury police on scene as well.
The bridge at Massey and Lee Valley Road has reopened, however nearby bands are still under lockdown.
Local school hold and secures have been lifted according to The Greater Sudbury Police.
Canine units, a SWAT team and a helicopter have been spotted in the area as well.
Both police and First Nations are asking the public to refrain from calling local bands and the police to keep the phones lines open.
Students of Biidaaban and Espanola High School are being taken care by staff until this situation is resolved.